Some electronic communication systems and global communication networks (e.g., the Internet and the World Wide Web) allow illegal sharing of digital files among users. For example, a first user may legally purchase a digital file (e.g., an audio file, a video file, an electronic book, or a software application), and may illegally transfer to a second user a digital copy of the digital file.
Typically, the entity which owns the legal rights in the digital file is not compensated for such illegal distribution (“piracy”). As a result, the price for legally purchasing the digital item may be increased, in order to compensate the rights owner for the losses resulting from piracy. The price increase, in turn, further increases the incentive of users to illegally obtain a copy of the digital file instead of legally purchasing the high-priced digital file.
Piracy further entails risks to the users who obtain illegal copies of the digital file. For example, some illegal copies may include malicious programs, e.g., a computer virus, a “spyware” module, or a fraud facilitating module. Furthermore, some users who attempt to obtain an illegal copy of the digital file may be exposed to undesirable materials, e.g., pornographic or offensive content, which may be provided by unauthorized distributors instead of or in addition to the illegal copy of the digital file.